Metal treating gas composition and apparatus for its preparation



F. M. FRANKHAUSER 3,291,581

AND APPARATUS FOR ITS PREPARATION Filed June 27, 1963 INVENTOR fiemm/cw Mq m nw/v/a/Awm BY I j 0/ 1 a; 66/

/6) f zRNEYs Dec. 13, 1966 METAL TREATING GAS COMPOSITION,

ullllilllllllll Illlll \l! United States Patent 3,291,581 METAL TREATING GAS COMPOSITION AND APPARATUS FOR ITS PREPARATIQN Frederick Meyer Franlihauser, Covina, Califl, assignor to Mite-Flo Inc, a corporation of California Filed June 27, 1963, Ser. No. 291,163 Claims. (Cl. 48-197) This invention relates generally to an assembly for humidifying a gas, the process of using the gas in heating metals to their melting temperature and composition of the gas. More particularly the present invention relates to a gas for heating a metal to its melting temperature as in brazing, metal coating, cutting and welding with reduced oxidation of the metal and with reduced production of free carbon.

There are numerous methods and gases known to the prior art for the cutting, welding etc, of metals; however, these methods and gases have been found to have inherent disadvantages in that not only are great amounts of the combustible gas or oxygen necessary but also there is a substantial formation of slag due to the oxidation of the metal and also a hardening of the metal due to the c-arbonization of the metal caused by the great amount of free carbon produced during the heating. Additionally during a cutting of metal, there is substantial amount of metal lost due to the size of the kerf. Usually it has been found that much of the metal lost is formed into an adhering slag that must be chipped or machined from the metal.

Accordingly it is the principal object of the present invention to provide an apparatus for producing a gas, a method for using the gas and a gas for the efiicient heating of metals to their melting temperature with greatly reduced oxidation and carbonization of the metal so heated.

Another object of the present invention is the provision of a combustible gas which may be used in welding, cutting, brazing or metals-praying and the like.

Another object of the present invention is to provide a combustible gas and method for heating metals to their melting temperature with the use of less combustible gas and oxygen.

Another object of the present invention is the provision of a gas and method for welding, brazing, cutting and spraying and the like which forms a minimum amount of slag and does not substantially increase the hardness of the metal.

A further object of the present invention is the provision of a combustible gas which permits accurate, smooth cutting of the metal with a small amount of lost metal.

This invention also has as an object the provision of a gas producing assembly which humidifies a gas and removes liquid droplets or mist that may be formed in the gas after ihumidification.

A further object of the present invention is the provision of a gas humidifying assembly which assures liquid gas contact for humidifying the gas and which includes apparatus for collecting the gas to provide for uniformity of composition and a trap to prevent undesired moisture from being incorporated into the gas.

These and other objects will be clear after a review of the following specification and drawings in which:

FIGURE 1 is a schematic elevational view, partly in section, showing the details of the gas treating assembly.

FIGURE 2 is a view of an alternate construction of the gas humidifier of the present invention showing a particular form of packing. The combustible gas treating assembly for producing a gas having improved properties which enable it to be used in welding, brazing, cutting and coating and the like is shown in FIGURE 1 and identified generally by the number "10. This gas treating 3,201,581 Patented Dec. 13, 3366 assembly includes a gas humidifier 12 and a gas receiving means 14. The gas humidifier is shown as being secured to the outside of the gas receiving means and while being shown in the form of an elongated enclosure its shape is not important.

The gas humidifier 12 includes a liquid inlet 16 and a combustible gas inlet 18 and a humidified gas outlet 20. The incoming gas is directed to a liquid gas contact means which is in the form of a conduit 22 which as shown extends beneath the level of the liquid 24 in the bottom of the humidifier 12. When so constructed, the gas entering the humidifier through the conduit 22 must be bubbled through the liquid 24 in order toexit from the humidifier.

While as shown the liquid gas contact means is in the form of a conduit 22, it is to be understood that any means such as an atomizer placed in the path of the incoming gas and sufiicient to add the proper amount of liquid to the gas would be satisfactory.

It has been found that any one or mixtures of the following gases could be used: butane, isobutane, propylene and propane. The liquid 24 is preferably water and it has been found that the amount of such moisture in the form of vapor should be within the limits of 1 to 5 lbs. per 10,000 ft. of the total gaseous mixture dry basis at standard conditions (5.0.) which are at a temperature of 60 F. and a pressure of 30 inches of mercury. The necessary moisture content of the gas may be also expressed as a 10 to 50% relative humidity at standard conditions dry basis.

The combustible gas after passing through the conduit 22 and bubbled through the liquid 24 may have liquid droplets or a mist formed in the gas. This mist or any liquid droplets should be removed prior to use of the gas in a cutting or welding and the like procedure. To remove these droplets the gas passes through a gas passageway between walls 26 which terminates in the humidifying gas outlet 20. Embodied within this gas passageway, as shown in FIGURE 1, are angularly disposed and vertically arranged bafiles 28 which provide openings 30 at their ends to permit passage of the gas upwards through the passageway. These baffles will cause the droplets of liquid to form on their surface and fall into the reservoir of liquid 24, thus permitting the gas with the necessary humidity to pass through the gas outlet 20.

FIGURE 2 shows the alternate construction of using packing such as Raschig rings which may be of ceramic materials. It is also possible to use any common tower packing in order to remove the liquid droplets from the humidified gas stream.

After the gas is humidified the necessary amount of oxygen and inert gas such as nitrogen, carbon dioxide, neon, helium and argon should be added. It is, of course, possible to add oxygen or the inert gas prior to the humidification and no significant difference should result as long as the moisture content of the gaseous mixture is within the limitation of l to 5 lbs. per 10,000 ft. (S.C.) dry basis.

As shown in FIGURE 1 the humidifid gas passes through pipe 32 into a compressor shown schematically at 34. The compressor is provided with a suitable air inlet 36 which is the source of oxygen and nitrogen. It has been found preferable to use air as the source of oxygen and nitrogen because of the economies involved. However, it is possible to achieve the same advantageous results if separate sources of oxygen and inert gases such as nitrogen, carbon dioxide, helium, neon and argon are used. The outlet for the compressor 38 is shown as entering the gas receiving means which is in the form of a tank or other enclosure 14. A safety emergency valve bypass 40 is shown and is recommended.

The gas which forms one of the features of the present invention after leaving the compressor is composed of 25-70% combustible gas such as propane, butane, isobutane, propane and mixtures thereof or any other liquefied petroleum product. The inert gas component should be 24 to 59% of one of the following: nitrogen, carbon dioxide, neon, helium or argon. The oxygen should be in the range of 6 to 16 percent and the moisture content in the form of water vapor should be 1 to lbs. per 10,000 ft. of the total gas mixture dry basis. All of the percentages indicated are by volume and under standard conditions dry basis.

The gas receiving means 14 is in the nature of a holding tank yet it includes unique features which enable the user to remove from this tank 14 gas of uniform composition. This tank also is constructed in a manner which enables it to withstand the usual pressures of 25 lbs. per sq. in. to 100 lbs. per sq. in. The gas enters the tank through elongated conduit 42 which directs the incoming gas to the bottom of the tank by means of the outlet 44. The humidified gas according to the present invention fills the receiving means 14 and is held therein until it is withdrawn. In order to withdraw the gas provision is made for obtaining uniform mixtures by reason of including a collecting means 46 Within the tank 14. This collecting means is an elongated closed conduit which has a plurality of vertically disposed inlets 48 which are in fluid communication with the interior of the conduit 46. The conduit 46 is in fluid communication with and is connected by means of pipe 50 to the trap means 52 which is shown as essentially a hemispherical enclosure suitably attached or secured by welding to the inside of the tank 14. At the base of the trap 52 is a drain hole 54 which may be used to drain any moisture or foreign matter that may collect in the trap. The outlet 56 is suitably secured to the wall of the tank 14 and communicates with the interior of the trap 52 to permit the withdrawal of the gas. The gas may be conducted to suitable metering apparatusnot shown or else directed to a torch tip, also not shown, for immediate use in the heating of metal to its melting temperature.

Also shown in the drawing are elements of the assembly which do not form a part of the present invention such as the pressure switch 58 and its accompanying gauge 60 which are suitably connected to the interior of the tank 14. Also motor 62 which drives the compressor 44 is shown.

The gas produced according to the present invention contains a combustible gas and an inert gas along with oxygen and water vapor. The inert gas is necessary in that it has been found that inclusion of inert gas in that amount specified in the present invention lends a protective coating to the working surface which has been heated by the ignited gas and by reason of this protective coating the amount of oxidation on the surface of the metal is considerably reduced. It accordingly has been found that considerably less slag is produced and accordingly far less metal is wasted. Among the advantages of this gas is also the significant fact that the kerf produced when cutting the metal with the gas is far less thanhas been experienced with the previously known gases.

A further advantage to the use of the inert component of the gaseous mixture according to the present invention is that inert gas acts as a diluent which allows control of the temperature at the burner tip. For instance, the more inert gas such as nitrogen is used, the lower is the temperature of the flame upon ignition and also there is less need for the oxygen.

In comparison with the gases commonly used, unhumidified propane will require 2.3% more cutting oxygen and 221% more preheating oxygen in addition to 113% more propane than the gaseous mixture according r 4 ture have been found with other commonly used gases such as natural gas.

One of the very important aspects of the present invention is the fact that less free carbon is produced on the working surface of the material. This is of significant value because the free carbon carbonizes the metal at the surface to harden the metal thus making it considerably more diflicult to machine. It has been found that the gas according to the present invention leaves the working surface of the metal in a state more nearly identical to its original condition than any other known gas. For instance it has been found that when gas of the present composition is compared with acetylene on several cuts of two-inch armor plate, the gas of the present invention results in Brinell hardness of 417 as compared with 573 for acetylene, thus amounting to a 27.2% reduction in hardness as compared with the commonly used acetylene. It has been theorized though not definitely established that the presence of moisture in the amount of 1 to 5 lbs. per 10,000 ft. gas (S.C.) dry basis reduces the amount of the free carbon produced upon ignition of the gas and accordingly significantly reduces the carbonization.

Other advantages accrue from the production of less carbon, such as a reduction in the clogging or fouling of torch tips. A further advantage of the gas. of the present invention is that by the use of less oxygen and less inert gas a lower heat is produced which can easily be controlled. For instance, common mixtures of acetyl ene and oxygen ignite at 4600 F. whereas thepresent composition of gas generally when ignited produces a temperature of approximately 3800". There is significant advantage in operating at lower temperature since excessive heat is not only expensive and wasteful but may cause buckling and damaging of the working surface. While welding, brazing, cutting and spraying of metal have been mentioned as the processes which utilize the gas of the present invention, it has also been found that the gas can be used for annealing, deseaming, scarfing, descaling, flame hardening, lead or rivet burning, ceramic and metal spraying, powder cutting, tool straightening and Weld gouging.

Specific examples of the gas according to the present invention are: p

All percentages by volume dry basis at (SC).

Example 1 Percent Propane 65.00 Oxygen 7.35 Nitrogen 27.65 Relative humidity 20.00

Example 2 Percent Propane 40.00 Oxygen 12.60 Nitrogen 47.40 Relative humidity 40.00

The gases of Examples 1 and 2 when under 25 pounds/in. pressure and passed through a conventional torch produce a clean cut of small kerf from a steelplate and are free from slag. Other metals such as aluminum, brass, copper produce similar results.

While the use of a propane, oxygen, nitrogen mixture is preferred results similar to the above can be obtained with the other combustible gases butane, isobutane and propylene and the other inert gases carbon dioxide, argon, neon and helium. The amount of the moisture vapor in the gas is not found to depend upon the composition of the gas.

I claim:

1. A combustible gas treating assembly for producing a gas having improved metal welding and cutting characteristics comprising a gas humidifier means and a gas receiving means, said gas humidifier means comprising a receptacle having at least one inlet for a combustible gas and a liquid for humidifying the gas and a humidified gas outlet, liquid gas contact means within said receptacle assuring intimate contact of said gas with said liquid, said receptacle being provided means for removing liquid droplets from the gas, means defining a gas passageway within said receptacle for housing said liquid removing means whereby said humidified gas passes through said liquid removing means and said outlet, fluid communication means between said humidifier means and receiving means, means secured to said assembly for adding oxygen to said combustible gas to form a gaseous mixture, means pressurizing said mixture, collection means within said receiving means for collecting gas at a plurality of predetermined locations therein, trap means communicating with said collection means and gas outlet means in said trap means.

2. A combustible gas treating assembly for producing a gas having improved metal welding and cutting characteristics comprising: a gas humidifier means and a gas receiving means, said gas humidifier means comprising a receptacle having at least one inlet for a combustible gas and a liquid for humidifying the gas and a humidified gas outlet, liquid gas contact means within said receptacle assuring intimate contact of said gas with said liquid, said receptacle being provided with vertically arranged bafiles, means defining a gas passageway within said receptacle for housing said baffles whereby said humidified gas contacts said liquid and passes through said baffies and said outlet, fluid communication means between said humidifier means and receiving means, means secured to said assembly for adding oxygen to said combustible gas to form a gaseous mixture, means pressurizing said mixture, collection means within said receiving means for collecting gas at a plurality of predetermined locations therein, trap means communicating with said collection means and gas outlet means in said trap means.

3. A combustible gas treating assembly for producing a gas having improved metal welding and cutting characteristics comprising a gas humidifier means and a gas receiving means, said gas humidifier means comprising a receptacle having at least one inlet for a combustible gas and a liquid for humidifying the gas and a humidified gas outlet, liquid gas contact means within said receptacle assuring intimate contact of said gas with said liquid, said receptacle being provided with vertically arranged packing for removing liquid droplets from the gas, means defining a gas passageway within said receptacle for housing said packing whereby said humidified gas passes through said packing and said outlet, fluid communication means between said humidifier means and receiving means, means secured to said assembly for adding oxygen to said combustible gas to form a gaseous mixture, means pressurizing said mixture, collection means within said receiving means for collecting gas at a plurality of predetermined locations therein, trap means communicating with said collection means and gas outlet means in said trap means.

4. A combustible gas treating assembly for producing a gas having improved metal welding and cutting characteristics comprising a gas humidifier means and a gas receiving means, said gas humidifier means comprising a receptacle having at least one inlet for a combustible gas and a liquid for humidifying the gas and a humidified gas outlet, liquid gas contact means within said receptacle assuring intimate contact of said gas with said liquid, said receptacle being provided with vertically arranged means for removing liquid droplets from the gas, means defining a gas passageway within said receptacle for housing said liquid removing means whereby said humidified gas passes through said liquid removing means and said outlet, fluid communication means between said humidifier means and receiving means, means secured to said assembly for adding oxygen to said combustible gas to form a gaseous mixture, means pressurizing said mixture, collection means within said receiving means for collecting gas at a plurality of predetermined locations therein, said collecting means comprising a plurality of vertically disposed inlets, trap means communicating with said collection means and gas outlet means in said trap means.

5. A combustible gas treating assembly for producing a gas having improved metal welding and cutting characteristics comprising a gas humidifier means and a gas receiving means, said gas humidifier means comprising a receptacle having at least one inlet for a combustible gas and a liquid for humidifying the gas and a humidified gas outlet, liquid gas contact means within said receptacle assuring intimate contact of said gas with said liquid, said receptacle being provided with vertically arranged means for removing liquid droplets from the gas, means defining a gas passageway within said receptacle for housing said liquid removing means whereby said humidified gas passes through said liquid removing means and said outlet, fluid communication means between said humidifier means and receiving means, means secured to said assembly for adding oxygen to said combustible gas to form a gaseous mixture, means pressurizin-g said mixture, collection means within said receiving means for collecting gas at a plurality of predetermined locations therein, trap means for retaining excess liquid obtained from said gas, said trap means communicating with said collection means and gas outlet means in said trap means.

6. A combustible gas treating assembly for producing a gas having improved metal welding and cutting characteristics comprising a gas humidifier means and a gas receiving means, said gas humidifier means comprising a receptacle having at least one inlet for a combustible gas and a liquid for humidifying the gas and a humidified gas outlet, liquid gas contact means within said receptacle assuring intimate contact of said gas with said liquid, said contact means comprising conduit means extending below a liquid level in said receptacle, said receptacle being provided with vertically arranged means for removing liquid doplets from the gas, means defining a gas passageway within said receptacle for housing said liquid removing means whereby said humidified gas passes through said liquid removing means and said outlet fluid communication means between said humidifier means and receiving means, means secured to said assembly for adding oxygen to said combustible gas to form a gaseous mixture, means pressurizing said mixture, collection means Within said receiving means for collecting gas at a plurality of predetermined locations therein, trap means for retaining excess liquid obtained from said gas, said trap means communicating with said collection means andgas outlet means in said trap means.

7. A combustible gas treating assembly for producing a gas having improved metal welding and cutting characteristics comprising: a gas humidifier means and a gas receiving means, said gas humidifier means comprising a receptacle having at least one inlet for a combustible gas and a liquid for humidifying the gas and a humidified gas outlet, liquid gas contact means within said receptacle assuring intimate contact of said gas with said liquid, said contact means comprising conduit means extending below a liquid level in said receptacle, said receptacle being provided with vertically arranged baffles, means defining a gas passageway within said receptacle for housing said baflles whereby said humidified gas contacts said liquid and passes through said baflles and said outlet, fluid communication means between said humidifier means and receiving means, means secured to said assembly for adding oxygen to said combustible gas to form a gaseous mixture, means pressurizing said mixture, collection means within said receiving means for collecting gas at a plurality of predetermined locations therein, trap means co'mmunicating with said c llection means and gas outlet means in said trap means.

8. A combustible gas treating assembly for producing a gas having improved metal Welding and cutting characteristics comprising a gas humidifier means and a gas receiving means, said gas humidifier means comprising a receptacle having at least one inlet for a combustible gas and a liquid for humidifying the gas and a humidified gas outlet, liquid gas contact means Within said receptacle assuring intimate contact of said gas with said liquid, said contact means comprising conduit mean-s extending below a liquid level in said receptacle, said receptacle being provided with vertically arranged means for removing liquid droplets from the gas, means defining agas passageway within said receptacle for housing said liquid removing means whereby said humidified gas passes through said liquid removing means and said outlet fluid communication means between said humidifier means and receiving means, means secured to said assembly for adding oxygen to said combustible gas to form a gaseous mixture, means pressurizing said mixture, collection means within said receiving means for collecting gas at a plurality of predetermined locations therein, said collecting means comprising a plurality of vertically disposed inlets, said trap means for retaining excess liquid obtained from said gas, said trap means communicating with said collection means and outlet means in said trap means.

9. A gaseous mixture for heating a metal to its melting temperature comprising: a gas selected from the group consisting of butane, isobutane, propylene and propane in the amount of 25 to 70% by volume (S.C.); a gas selected from the group consisiting of nitrogen, carbon dioxide, neon, helium and argon in the amount of 24 to 59% by volume (S.C.); 6 to 16% oxygen by volume (SC) and 1 to 5 pounds Water vapor per 10,000 ft. of gas mixture (S.C.) dry basis.

10. The gaseous mixture of claim 9 wherein the water Vapor is present in the amount of 10 to relative humidity.

References Cited by the Examiner UNITED STATES PATENTS 724,416 4/1903 Amet 48197 1,806,049 5/1931 Ennis et al -259 X 2,136,075 11/1938 De Motte 48192 2,211,448 8/1940 Vaughn an 261-121X 2,280,029 4/1942 Crowe 158-199 x 2,408,282 9/1946 Wolf 23-277 2,800,175 7/1957 Sharp 263-52 X 3,035,947 5/1962 Milton etal 148 9.5

FOREIGN PATENTS 233,149 3/1961 Australia MORRIS O. WOLK, Primary Examiner.

JOSEPH SCOVRONEK, Examiner. 

9. A GASEOUS MIXTURE FOR HEATING A METAL TO ITS MELTING TEMPERATURE COMPRISING: A GAS SELECTED FROM THE CONSISTING OF BUTANE, ISOBUTANE, PROPYLENE AND PROPANE IN THE AMOOUNT OF 25 TO 70% BY VOLUME (S.C.); A GAS SELECTED FROM THE GROUP CONSISTING OF NITROGEN, CARBON DIOXIDE, NEON, HELIUM AND ARGON IN THE AMOUNT OF 24 TO 